Nanomaterials for Diagnosis: Challenges and Applications in Smart Devices Based on Molecular Recognition

Abstract

Clinical diagnosis has always been dependent on the efficient immobilization of biomolecules in solid matrices with preserved activity, but significant developments have taken place in recent years with the increasing control of molecular architecture in organized films. Of particular importance is the synergy achieved with distinct materials such as nanoparticles, antibodies, enzymes, and other nanostructures, forming structures organized on the nanoscale. In this review, emphasis will be placed on nanomaterials for biosensing based on molecular recognition, where the recognition element may be an enzyme, DNA, RNA, catalytic antibody, aptamer, and labeled biomolecule. All of these elements may be assembled in nanostructured films, whose layer-by-layer nature is essential for combining different properties in the same device. Sensing can be done with a number of optical, electrical, and electrochemical methods, which may also rely on nanostructures for enhanced performance, as is the case of reporting nanoparticles in bioelectronics devices. The successful design of such devices requires investigation of interface properties of functionalized surfaces, for which a variety of experimental and theoretical methods have been used. Because diagnosis involves the acquisition of large amounts of data, statistical and computational methods are now in widespread use, and one may envisage an integrated expert system where information from different sources may be mined to generate the diagnostics.

Where Chemical Sensors May Assist in Clinical Diagnosis Exploring “Big Data”

“…The field of chemical sensors has witnessed enormous progress in the past decades in several directions: sensitivity has increased, in some cases reaching the single molecule level; 4 selectivity has also been enhanced in biosensors with specific interactions with which clinical diagnosis may be performed; 5 sensors are now integrated into devices aimed at therapeutic action in addition to diagnosis, within the so-called theranostic paradigm. 6 These developments were made possible with tremendous progress in the materials used for sensing, in the architecture of the sensing devices and in the detection methods.…”

“…6 These developments were made possible with tremendous progress in the materials used for sensing, in the architecture of the sensing devices and in the detection methods. 5 Just by way of illustration, novel materials include ionic liquids, graphene or other carbon-based materials, nanoparticles, quantum dots, and a whole host of biomolecules, including DNA. The variety of methods for detection is also immense and does not stop growing.…”

Highly sensitive detection of 2,4,6-trichlorophenol based on HS-β-cyclodextrin/gold nanoparticles composites modified indium tin oxide electrode

“…The small size, high surface-to-volume ratio, good biocompatibility and unusual target binding characteristics can markedly improve the sensitivity and specificity of analyte detection, making nanomaterials particularly appealing for use as chemical and biomedical sensors [27][28][29][30]. Metal nanoparticles, especially gold nanoparticles (AuNPs), have been extensively studied because of their attractive physicochemical characteristics, such as good electrical conductivity, biocompatibility, and excellent environmental stability [31].…”

Interfacing nanomaterials for bioelectronic applications

“…56, 59 The use of nanomaterials as an interface element on their own or as part of a hybrid structure, allows new properties to be exploited in the area of bioelectronics. The different types of nanomaterials, from metal or semiconductor nanoparticles to the 2D carbon-based structure, have an important ability to provide suitable platforms for interfacing nanomaterials for bioelectronic applications.…”

“…They have been employed mainly in catalytic and electro-catalytic applications where they provide a high surface area to mass ratio and promote particular reaction pathways. 59 A key aspect of the study of interfacing nanoparticles is to prepare and characterise a nanostructured surface of an electrode. There are two main reasons for using support electrodes.…”